Crafting is not expensive to pursue, but you have to do your own harvesting. You'll pay a lot for certain raw materials if you buy them from other players on the broker. At level 20 you can start doing writs which will reimburse you for fuel costs and pay you a little extra in profit and status for you and your guild. The best way to level is to do each new recipe you get to pristine to get the bonus experience and then do writs until the next level. When you know what you're doing timed writs will make you more, but you can fail and lose the profit and payment for one set of fuel. If you harvest yourself and do writs all your costs for non-rare crafting will be covered.
My main is a 70 weaponsmith and I've leveled a crafter to at least 30 in every profession but tailoring. Tradeskills are a rough way to make money these days. No tradeskill will make you anything before level 30 or 40. There are many crafters in the market since a recent update that overhauled tradeskills made it easier and more appealing to many players. There are also 2 high level Heritage Quests that require a fairly high crafting level to complete, bringing more people into crafting. The broker if awash with common crafted items selling at prices at or even below the cost to make them.
A situation has developed on many servers for various rare crafted items if you plan to buy raws on the broker. The selling price of the finished item is lower than the cost of the rare raw material and fuel so you can't make any profit.
As in all things, there are exceptions - if you're vigilant. Certain items may be in low supply on your server and will sell for decent money, or you can find bargains on rares. Exactly what items they are changes all the time so you have to keep on top of the broker. That's more work than some people want to put into tradeskills.
Finally, there has been an overall slowdown in the rate of sales on everything I make. Not sure if it's because school is back in session, there's a new expansion imminent or what.
I expect a boom when the expansion goes live as everyone twinks out their new Fae alts. I plan to spend lots of time harvesting in lower tiers and filling up my broker boxes.